Sleeping Bags continue to evolve this year. It seems everyone now has "lightweight" products in their line. Some manufacturers' idea of lightweight would be laughed at by most Backpackinglight readers, but still, even mainstream companies like Lafuma now have lighter bags, and at a lower price than the premium niche-market lightweight products available in the past.
This year also sees increased adoption of technologies like laminated insulation. First introduced decades ago in heavyweight bags by Wiggy's, welding or laminating the insulation to the shell and/or liner of a bag simplifies construction, and eliminates the need for quilting, scrim, and baffles to stabilize the insulation. The North Face, Marmot, and Mountain Hardwear now have lightweight bags with this construction.
Several new bags save weight through innovative features and new materials. New proprietary synthetic insulations, as well as widely available Climashield are now appearing. A new non-calendered, down-proof shell material also debuts in a Montbell bag.
Lafuma Pro 650g Down Bag. A conventional mummy bag with 750+ fill-power down and a 20d Polyamide shell. This bag shows how mainstream companies are getting lighter. This bag has an MSRP of only $190. That's not bad for a 25°F 750+ FP down bag that weighs 23oz (claimed).
Marmot Mountain 30 Bag. Marmot laminates their new proprietary, continuous, high-void insulation called Thermaclime to the shell to eliminate stitching and reduce weight. Strangely, they stitch a second insulation layer to the bag's liner, claiming that the stitched construction has improved breathability over laminating due to the glue used in lamination. I expect this will provide a nice next-to-skin feel, but will result in diminishing air permeability as you move from the skin out that may trap more moisture in the bag than if the construction were reversed with the laminated layer on the inside. The $139 MSRP bag is rated at 30°F and weighs 2 lb, 3oz (claimed).
The North Face Propel Bag with welded insulation construction. We reported on the Pertex Quantum shelled Propel bag with welded Polarguard Delta insulation at ORSM 2004. Since then, the Propel bag has gained a vented footbox, and switches this year to Climashield insulation. Both of these changes unfortunately add weight to the bag, now at 19 oz (claimed). A full review of the updated Propel is planned.
Western Mountaineering Summerlite Bag. We first covered this bag at ORWM 2005. At 18oz with full zip and 4 inches of fully-baffled single layer loft (claimed), it remains the lightest standard mummy bag for its loft. Gary Schaezlein, the owner of Western Mounteering, says that his company has been swamped fulfilling orders for existing products and has pushed back availability of this bag to Spring 2007. Don Wilson has been using this bag on the PCT this summer. We'll publish a complete review soon.
Montbell ul super stretch down hugger bag with new 800 fill-power down and revised the shell fabric. The new lightweight non-calendered but still down-proof shell fabric promises enhanced breathability. The use of 800 fill-power down puts it more in line with competitors' premium down products.
Big Agnes King Solomon. A 600 fill-power down couples top bag rated at 15°F and weighing 4lb, 12oz (claimed). What can I say? Alan and Alison look pretty comfortable in it. Actually, it is fairly weight efficient for a 15 degree bag at 38 ounces per person - just choose your bag mate carefully.
Mountain HardWear Men’s UltraLamina 45 Synthetic Bag. Using a new proprietary short-staple insulation called Thermic Micro, claimed to be 50% easier to stuff than their older Thermic CF, this bag offers dual zip entry with half-zips extending from the neck on either side of the bag. This allows the user to sit up and use their arms to cook or read like in similar bags from Nunatak, Feathered Friends, and Exped. MH is using the new insulation throughout their bag line this year. It's laminated to the shell in this bag, hence the UltraLamina name. 1 lb 8oz, MSRP $165.